I think you're confusing li-poly and lithium ion, with lifepo4. There's no shortage of videos on youtube of people cutting open lifepo4 with kitchen knives, band saws, and hammers without ill effect.
False equivalence IMO... cutting into an unconnected battery is not how battery fires typically start, not a typical act people perform with their batteries, nor really related to self-ignition, dendrites or thermal runaway at all.
If you want to look at it from another angle, you often can't get insurance for a boat with "regular" lithium house batteries, however most/all insurance companies have a carve-out for lifepo4 as it's recognized industry-wide as one of the safest battery technologies available under a wide variety of conditions.
